BigWeakSauce

The air ride systems are self regulating, when a pressure sensor reads low pressure the compressor will kick on until the threshold is reached. If it keeps kicking on, you almost certainly have a leak somewhere... The compressor is normally located just behind the rear driver side wheel, if the sound is coming from anywhere else, that is likely the location of your issue. As the compressor begins to fail it will get louder and it will sound like it's struggling to keep up, it may not kick on at all once it's failed, at that point you should notice significant ride quality issues. They aren't designed to draw voltage for long periods of time so a small leak can damage the compressor quickly, which is why out of nowhere your compressor might be so loud. A dealer or repair shop with the diagnostic reading system (call and ask) can actually see exactly where the leak is on the computer. Through the software they can manually turn the compressor on and see exactly what sensor or component is failing. The software shows pressure readings and you can deduce from that data where your leak is. A lot of dealers won't have the patience to trigger the compressor and wait to see what leaks, especially if the leak takes several minutes to show up, they may simply see everything filled correctly and move on. I don't know how to do it but there is a way to put a gauge on your shocks to manually read pressure, that may help if your leak is really slow. And just FYI the system will show what component is as at fault but not necessarily why. So if you pay to replace a sensor that goes bad again quickly, the true problem is likely in the wiring. The harnesses on these vehicles have a tendency to rub through and damage the wires after high miles. And if you replace the compressor and it goes bad again quickly it's probably a leak wearing it out or a wiring issue supplying incorrect voltage. Normally the dealer charges like $100-150 to diagnose for you, credited toward the cost of repair, look it up on youtube and you can see what they see on the screen and how easy it is to see where the problem is. It's very frustrating to put your vehicle in the shop only to get it back without a good solution, I hope this helps someone!